Implant and delivery tool therefor

ABSTRACT

An implant comprises: (a) an implant body that comprises: (i) at least a first longitudinal portion of the implant body that defines a given outer diameter; and (ii) a recessed longitudinal portion of the implant body that is radially recessed with respect to the first longitudinal portion of the implant body, such that an outer diameter of the recessed longitudinal portion is less than the outer diameter of the first longitudinal portion; and (b) a cuff coupled to the implant body around the recessed longitudinal portion of the implant body such that an outer diameter of the cuff does not exceed the outer diameter of the first longitudinal portion. The cuff defines a plurality of holes that are configured to facilitate anchoring of the implant body with respect to the subject&#39;s tissue, by facilitating tissue growth into the holes. Other embodiments are also described.

CROSS-REFERENCES TO RELATED APPLICATIONS

This patent application is a Continuation of U.S. Ser. No. 16/934,692 to Oron et al., filed Jul. 21, 2020, and entitled “IMPLANT-DELIVERY TOOL,” which published as US 2020-0346020 to Oron et al., and which is a Continuation of U.S. Ser. No. 16/183,783 to Oron et al., filed Nov. 8, 2018, and entitled “Implant and delivery tool therefor,” which issued as U.S. Pat. No. 10,744,331 to Oron et al., and which is a Continuation of U.S. Pat. No. 15/360,501 to Oron et al., filed Nov. 23, 2016, and entitled “Implant and delivery tool therefor,” which issued as U.S. Pat. No. 10,124,178.

FIELD OF THE INVENTION

The present invention relates generally to medical devices, and specifically to apparatus and methods for use with percutaneous implants.

BACKGROUND

Neurological disorders affect the nerves, muscles or the brain. Many neurological disorders reduce or eliminate voluntary recruitment of muscles, which may result in loss of ability to perform motor tasks or to maintain systems that depend on muscle activity for their function. Other disorders may cause pain to adjacent tissues.

Neurostimulation is a clinical tool used to treat various neurological disorders, and involves modulation of the nervous system by electrically activating fibers in the body.

SUMMARY OF THE INVENTION

For some applications of the invention, a system is provided comprising an implant, and a delivery tool therefor. The implant has an antenna and at least one electrode. The delivery tool comprises a hollow needle that typically has lateral openings. The delivery tool has discrete states. Typically, in a first state, the implant is entirely housed by the needle, and/or the antenna is disposed proximally from the lateral openings in the needle. Typically, in a second state, a distal portion of the implant is exposed out of the distal end of the needle, and/or the antenna is aligned with the lateral openings. In a third state, the implant is entirely disposed outside of the distal end of the needle. The system (i) facilitates testing of potential implantation sites for the implant, and (ii) increases the safety of advancing implants close to nerve tissue.

For some applications of the invention, the needle defines, at its distal end, a triple-grind bevel that defines (i) a primary grind, and (ii) two side-grinds that do not extend to meet each other to define a point at a distal-most part of the needle. This triple-grind bevel may be used for needles other than that of the delivery tool described herein.

For some applications, the implant defines a recessed portion around which a cuff is disposed, the cuff facilitating anchoring of the implant.

There is further provided, in accordance with an application of the present invention, apparatus for facilitating percutaneous delivery of an implant to a target site of a body of a subject, the implant including an antenna, and the apparatus including:

a delivery tool including a hollow needle that defines lateral openings in a wall of the needle, the hollow needle being configured to house the implant,

the delivery tool being configured to define:

-   -   a first state, in which the implant is housed by the needle such         that the antenna is disposed proximally from the lateral         openings,     -   a second state, in which a distal portion of the implant is         exposed from a distal end of the needle, and the antenna is         aligned with the lateral openings, and     -   a third state, in which the implant is entirely disposed outside         of the distal end of the needle.

In an application, in the first state, the entire implant is disposed within the needle.

In an application, in the first state, the entire implant is disposed proximally from the lateral openings.

In an application, in the first state, the distal portion of the implant is aligned with the lateral openings.

In an application, the hollow needle is a hollow metal needle.

In an application, the hollow needle defines a triple-grind bevel at the distal end of the needle, the triple-grind bevel defining:

a primary grind, and

two side-grinds that do not extend to meet each other to define a point at a distal-most part of the needle.

In an application, the apparatus further includes the implant.

In an application:

the implant is an electrostimulator implant, and includes:

-   -   an implant body, the implant being injectable into tissue of a         subject along a longitudinal axis of the implant body;     -   a proximal electrode, and a distal electrode disposed on the         implant body distally from the proximal electrode, and

in the second state of the delivery tool, the distal electrode is exposed from the distal end of the needle.

In an application, in the first state of the delivery tool, the proximal electrode and the distal electrode are disposed within the needle.

In an application, the antenna is configured to receive energy wirelessly.

There is further provided, in accordance with an application of the present invention, a method for percutaneously delivering an implant to a target site of a body of a subject, the method including:

inserting into tissue of the subject a hollow needle of a delivery tool, while the delivery tool is in a first state, in which the implant is entirely housed within the needle and no portion of the implant is exposed through the lateral openings in the needle wall;

subsequently, switching the delivery tool to a second state, in which a distal portion of the implant is exposed from a distal end of the needle, and a proximal portion of the implant is at least partially exposed through lateral openings defined by the needle wall; and

subsequently, switching the delivery tool to a third state, in which the implant is entirely disposed outside of the distal end of the needle.

In an application, the method further includes, while the delivery tool is in the second state, advancing the delivery tool and the implant distally within the body of the subject.

There is further provided, in accordance with an application of the present invention, a method for percutaneously delivering an implant through a region of a body of the subject to a target site of the body, the region including a fascia and non-fascia tissue, the method including:

advancing, distally through the fascia, a hollow needle of a delivery tool, while the delivery tool is in a first state in which the implant is entirely housed within the needle;

switching the delivery tool to a second state in which a proximal portion of the implant is housed within the needle, and a distal portion of the implant is exposed from a distal end of the needle; and

while the delivery tool is in the second state, advancing the hollow needle distally through non-fascia tissue.

In an application, the method further includes, prior to advancing the hollow needle distally through the fascia, switching the delivery tool into the first state.

In an application, the method further includes, prior to switching the tool into the first state, advancing the hollow needle distally through non-fascia tissue toward the fascia while the tool is in the second state.

In an application, the method further includes, subsequently to the step of advancing the hollow needle distally through the non-fascia tissue while the delivery tool is in the second state, switching the delivery tool to a third state, in which the implant is entirely disposed outside of the distal end of the needle.

In an application, the method further includes, while the delivery tool is in the third state, releasing the implant from the delivery tool.

There is further provided, in accordance with an application of the present invention, apparatus for facilitating percutaneous delivery of an implant to a target site of a body of a subject, the apparatus including:

a needle including:

-   -   a distal end; and     -   a proximal end,     -   the needle defining:         -   a lumen configured to facilitate passage of the implant             therethrough, and         -   a triple-grind bevel at the distal end of the needle, the             triple-grind bevel defining:             -   a primary grind, and             -   two side-grinds that do not extend to meet each other to                 define a point at a distal-most part of the needle.

In an application, the needle defines lateral openings in a wall of the needle, the openings being proximal from the distal end of the needle.

In an application, the needle is a metal needle.

In an application, the two side-grinds converge distally at an angle of 65-85 degrees to each other.

In an application, the primary grind defines an angle of 15-25 degrees with respect to a central longitudinal axis of the needle.

In an application, the side-grinds converge distally, but at the distal-most part of the needle, the side-grinds are spaced apart by 0.1-0.4 mm.

There is further provided, in accordance with an application of the present invention, a method for percutaneously delivering an implant to a target site of a body of a subject, the method including:

inserting the implant into the subject's tissue;

activating the implant to apply a current to the subject's tissue at a first site within the tissue at a first power level;

measuring a response of the subject to the application of the current to the first site at the first power level;

in response to detecting that the subject responded in a given manner to the application of the current to the first site at the first power level, iteratively applying current to the first site at iteratively lower power levels until detecting that, at a second power level, the subject no longer responds, in the given manner, to the application of current to the first site; and

subsequently:

-   -   moving the implant to one or more further sites within the         subject's tissue and applying current to the tissue, at the one         or more further sites, at the second power level;     -   measuring a response of the subject to the application of         current to the subject's tissue at the one or more further         sites; and     -   in response to detecting that the subject responds, in the given         manner, to application of the current at the second power level         at a given one of the one or more further sites, implanting the         implant closer to the given site than to the first site.

In an application:

inserting the implant includes inserting the implant while the implant is at least partly disposed within a hollow needle of a delivery tool,

moving the implant includes moving the implant while the implant is at least partly disposed within the hollow needle, and

activating the implant includes activating the implant while (i) the implant is at least partly disposed within the hollow needle, and (ii) an electrode of the implant is exposed from a distal end of the hollow needle.

In an application, activating the implant includes wirelessly activating the implant while an antenna of the implant is aligned with a lateral opening in a wall of the hollow needle.

In an application, moving the implant includes moving the implant while the electrode of the implant remains exposed from the distal end of the hollow needle.

There is further provided, in accordance with an application of the present invention, apparatus including:

an implant configured to be implanted in tissue of a subject, the implant including:

-   -   an implant body that includes:         -   at least a first longitudinal portion of the implant body             that defines a given outer diameter; and         -   a recessed longitudinal portion of the implant body that is             radially recessed with respect to the first longitudinal             portion of the implant body, such that an outer diameter of             the recessed longitudinal portion is less than the outer             diameter of the first longitudinal portion; and     -   a cuff coupled to the implant body around the recessed         longitudinal portion of the implant body such that an outer         diameter of the cuff does not exceed the outer diameter of the         first longitudinal portion,     -   the cuff defining a plurality of holes that are configured to         facilitate anchoring of the implant body with respect to the         subject's tissue, by facilitating tissue growth into the holes.

In an application, the cuff extends less than 360 degrees around the recessed longitudinal portion.

In an application, each hole of the plurality of holes has a diameter of 200-550 microns.

In an application, the cuff has a thickness of 200-550 microns.

In an application, the implant further includes an antenna, disposed within the recessed longitudinal portion.

In an application, the recessed longitudinal portion does not include a distal end or a proximal end of the implant.

In an application, the cuff includes a resilient material.

In an application, the apparatus further includes a delivery tool that includes a hollow needle through which the implant is slidable, and the outer diameter of the cuff is such that the cuff does not grip the inside of the hollow needle.

In an application, the hollow needle defines a triple-grind bevel at a distal end of the needle, the triple-grind bevel defining:

a primary grind, and

two side-grinds that do not extend to meet each other to define a point at a distal-most part of the needle.

The present invention will be more fully understood from the following detailed description of applications thereof, taken together with the drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-C are schematic illustrations of a system comprising an implant and a delivery tool therefor, in accordance with some applications of the invention;

FIGS. 2A-H are schematic illustrations of a technique for using the delivery tool to implant the implant, in accordance with some applications of the invention;

FIGS. 3A-D are schematic illustrations of a tip of a needle of the delivery tool, in accordance with some applications of the invention; and

FIGS. 4A-C are schematic illustrations of the implant, in accordance with some applications of the invention.

DETAILED DESCRIPTION OF EMBODIMENTS

Reference is made to FIGS. 1A-C, 2A-H, 3, and 4A-C, which are schematic illustrations of a system 20 and techniques for using the system, in accordance with some applications of the invention. System 20 comprises an implant 40, and a delivery tool 100 for percutaneous implantation of the implant.

Implant 40 comprises an implant body 42, circuitry 44 and an antenna 46 disposed within the implant body, and at least one electrode 48 (e.g., a proximal electrode 48 p and a distal electrode 48 d) disposed on the outside of the implant body. Implant 40 has a proximal portion 50 p (e.g., a proximal half) that includes a proximal end of the implant, and a distal portion 50 d (e.g., a distal half) that includes a distal end of the implant. Typically, at least one of electrodes 48 (e.g., a distal electrode 48 d) is disposed at distal portion 50 d. Typically, antenna 46 is disposed proximally from that at least one electrode 48. For example, antenna 46 may be disposed proximally from distal portion 50 d, such as within proximal portion 50 p.

At proximal portion 50 p (e.g., at the proximal end) of implant 40, the implant (e.g., implant body 42) defines an implant-coupling 52 that is reversibly couplable to a complementary tool-coupling of tool 100.

Tool 100 comprises a hollow needle 102 at a distal part of the tool, and a control portion 104 at a proximal part of the tool, the control portion typically comprising a handle 106. Needle 102 has a lateral wall that circumscribes a longitudinal axis axl of the needle to define a lumen along the longitudinal axis. Needle 102 defines lateral openings 108 (e.g., longitudinal slits) in the lateral wall. Tool 100 is configured to define at least three states, which are shown in FIGS. 1 -C, respectively.

FIGS. 1A-C show implant 40 loaded in tool 100. In the first state (FIG. 1A), implant 40 is housed by needle 102 such that antenna 46 is disposed proximally from openings 108. For some applications, in the first state the entire of implant 40 is disposed proximally from openings 108 (i.e., proximally along longitudinal axis axl of needle 102). Alternatively, and as shown, some of the implant (e.g., distal portion 50 d) is aligned with openings 108 (i.e., disposed at the same part of longitudinal axis axl of needle 102), and/or distally from the openings (i.e., distally along the longitudinal axis of needle 102). Typically, and as shown, in the first state, all of electrodes 48 are disposed within needle 102 (i.e., the lumen thereof). For example, and as shown, in the first state, implant 40 may be disposed entirely within needle 102.

In the second state (FIG. 1B), distal portion 50 d of implant 40 is exposed from the distal end of needle 102, and antenna 46 is aligned with openings 108 (i.e., disposed at the same part of longitudinal axis axl of the needle). Typically, in the second state, electrode 48 d is exposed from the distal end of needle 102.

In the third state (FIG. 1C), implant 40 is entirely disposed outside of the distal end of needle 102.

Implant 40 is an electrostimulator implant, and drives electrodes 48 to apply current to tissue of the subject in which the implant is implanted. Implant 40 is controlled and/or powered wirelessly, e.g., by transmitting wireless signals from an extracorporeal controller (not shown). Such signals are received by antenna 46. Needle 102 is typically metallic. Openings 108 allow such wireless signals to pass into the lumen of needle 102. Other parts of needle 102 are relatively opaque to such signals. During implantation of implant 40, and before final deployment (i.e., release) of the implant, the implant is activated such that it drives electrodes 48 to apply current to the tissue, in order to determine if its current location within the tissue is an effective location for implanting the implant (e.g., by determining if its desired effect on the subject occurs). The inventors hypothesize that it is advantageous to prevent the operator (e.g., the physician) from inappropriately and/or inadvertently activating implant 40 (e.g., at an inappropriate time). In the first state, the wireless signals cannot reach (or cannot sufficiently reach) antenna 46. Therefore, the testing of the position of implant 40 cannot be performed in the first state. In the second state, the wireless signals can reach antenna 46, and therefore it is possible, in the second state, to test the position of implant 40. (Naturally, the wireless signals can reach antenna 46 also when tool 100 is in the third state, because in the third state implant 40 is entirely disposed outside of the distal end of needle 102.)

The use of openings 108 is particularly useful for applications in which the material from which needle 102 is formed is opaque to the wireless signals (e.g., a metal). For some applications, the material from which needle 102 is primarily formed may be transparent to the wireless signals (e.g., a polymer). For some such applications, needle 102 may have a metallic portion (e.g., a metallic shell radially inside, outside, or within the polymer, or as a distinct metallic longitudinal section between more proximal and distal polymer longitudinal sections), at the part of the needle at which antenna 46 is disposed in the first state of tool 100. The metallic portion inhibits the wireless signal from reaching (or sufficiently reaching) antenna 46, as described hereinabove, mutatis mutandis. Therefore, in a similar way to that described hereinabove, such a needle would also prevent inappropriate/inadvertent activation of implant 40 while tool 100 is in the first state, but would allow activation of the implant while the tool is in the second state. In a similar way, for some applications needle 102 may be primarily formed from a metal, but openings 108 are replaced by a polymer portion of the needle.

The embodiments described above have the following in common:

-   -   The hollow needle has (i) a non-blocking longitudinal portion         that allows the wireless signal to reach the antenna while the         antenna is disposed in the non-blocking portion, and (ii) a         blocking longitudinal portion that is significantly more opaque         to the wireless signal than is the non-blocking portion, such         that it blocks the wireless signal from activating the implant         while the antenna is disposed in the blocking portion.     -   In the first state of the tool, the antenna is disposed in the         blocking portion of the needle.     -   In the second state of the tool, the antenna is disposed in the         non-blocking portion of the needle.     -   In the third state of the tool, the implant is entirely disposed         outside of the distal end of the needle.     -   Typically, the non-blocking portion is closer than the blocking         portion to the distal end of the needle.

For applications in which (i) in the first state all of electrodes 48 are disposed within needle 102, and (ii) in the second state electrode 48 d is exposed from the distal end of the needle, the differing position of the electrodes between the first and second states may further prevent inappropriate and/or inadvertent driving of the current by implant 40. That is, in the first state, implant 40 cannot receive the wireless signals, and electrodes 48 are not exposed for application of current, whereas in the second state, implant 40 can receive the wireless signals, and at least one of electrodes 48 is exposed for application of current.

It is to be noted that, in the context of the first, second and third states of tool 100, the term “state” (including in the specification and the claims) means a discrete pre-configured condition of the tool, such as a condition in which the tool is configured to remain. Thus, tool 100 being configured to define the states means that tool 100 has particular features or elements that define the states and/or retain the tool in the states. For example, tool 100 (e.g., control portion 104) may comprise control elements 110 that enable switching between the states.

FIGS. 2A-H show steps in a technique for using tool 100 to implant implant 40 in a subject, in accordance with some applications of the invention. The example used is implantation of implant 40 close to a tibial nerve 6 of the subject, and in a distal to proximal direction, but the technique may be used at other anatomical sites and/or in other anatomical directions, mutatis mutandis. Each of FIGS. 2A-H shows a longitudinal cross-section and a transverse section of the lower leg 4 of a subject. The longitudinal cross-section illustrates the advancement of needle 102 through the tissue, and the state of tool 100. The transverse cross-section provides more anatomical detail, and schematically shows the depth to which needle 102 has penetrated. In the transverse cross-section, the element labeled 102 schematically represents needle 102. However, although in the transverse cross-section needle 102 should extend into and/or out of the page, a more simple representation is used for the sake of clarity.

Needle 102 (e.g., a tip 120 thereof) is percutaneously advanced into the leg (FIG. 2A). For some applications, and as shown, needle 102 is advanced through the skin while tool 100 is in the first state, with tip 120 thereby defining the leading edge of system 20, e.g., such that needle 102 penetrates the skin. (Alternatively, an incision is made in the skin, and tool 100 is introduced via the incision, e.g., while in the second state). Subsequently, tool 100 is switched to the second state (FIG. 2B). Subsequently, and while tool 100 is in the second state, it is advanced through non-fascia tissue (e.g., fat tissue, and/or connective tissue) 8 of the leg, typically until reaching a fascia 10 (FIG. 2C). That is, system 20 is advanced through the non-fascia tissue with implant 40 distal to needle 102, and defining the leading edge of system 20. Upon reaching a fascia 10, tool 100 is switched to the first state (FIG. 2D), and advanced through the fascia while in the first state (FIG. 2E). Once through the fascia, the tool is switched to the second state (FIG. 2F), and advanced through more tissue 8 (FIG. 2G). As described hereinabove, in the second state it is possible to determine if the current location of implant 40 within the tissue is an effective location for implanting the implant. Once a suitable location of implant 40 is achieved (FIG. 2G), tool 100 is switched to the third state (FIG. 2H). Implant 40 is deployed (i.e., released from tool 100) at the suitable location, e.g., automatically upon tool 100 being switched to the third state, or as a result of a distinct subsequent deployment step.

As described hereinabove, determining that implant 40 is in a suitable location for implantation is achieved by activating the implant and, for example, detecting if the desired effect of the implant on the subject has occurred. It is hypothesized by the inventors that, for some applications, such a technique may be limited when the implant is activated to apply current at a single power level. For example, when a single power level is used, if an effect on the subject is detected when the implant is at a first site, and an effect on the subject is also detected when the implant is at a second site, the technique will not have provided information on which of the two sites is more suitable (e.g., closer to nerve 6). It is hypothesized by the inventors that such a technique may be improved by varying the power level at which implant 40 applies current to the tissue in which it is disposed. For example, if (1) after the effect is detected when the implant is at the first site, the implant is activated again, but using iteratively lower power levels until the effect is reduced (e.g., to below a threshold level, such as until the effect is not detected), and (2) when the lower power level is used at the second site, the effect is detected (and/or is above the threshold level), this indicates that the second site is more suitable (e.g., closer to nerve 6) than is the first site.

There is therefore provided, a method for percutaneously delivering an implant to a target site of a body of a subject, the method comprising:

(1) inserting the implant into the subject's tissue;

(2) activating the implant to apply a current to the subject's tissue at a first site within the tissue at a first power level;

(3) measuring a response of the subject to the application of the current to the first site at the first power level;

(4) in response to detecting that the subject responded in a given manner to the application of the current to the first site at the first power level, iteratively applying current to the first site at lower power levels, until detecting that, at a second power level, the subject no longer responds, in the given manner, to the application of current to the first site; and

(5) subsequently:

-   -   (a) moving the implant to one or more further sites within the         subject's tissue and applying current to the tissue, at the one         or more further sites, at the second power level;     -   (b) measuring a response of the subject to the application of         current to the subject's tissue at the one or more further         sites; and     -   (c) in response to detecting that the subject responds, in the         given manner, to application of the current at the second power         level at a given one of the one or more further sites,         implanting the implant closer to the given site than to the         first site.

For applications in which movement of the implant between the sites being tested does not require further penetration of a fascia, this movement of the implant between the sites is typically performed while the delivery tool remains in the second state.

Tip 120 is a beveled tip for penetrating tissue. It is hypothesized by the inventors that beveled tips are important for penetrating fascia 10 (and typically also skin 12), but that some other tissues (e.g., fat tissue and/or connective tissue) can be penetrated by implant 40 itself. Thus, in the technique shown in FIGS. 2A-H, implant 40 is advanced through tissue 8 while tool 100 is in the second state, thereby (as described hereinabove) facilitating identification of an effective location for implanting implant 40. It is further hypothesized by the inventors that as implant 40 becomes close to a target nerve such as tibial nerve 6, advancing the implant while tool 100 is in the second state reduces a likelihood of injuring the nerve or a nearby blood vessel with tip 120.

It is to be noted that the transition of tool 100 between its states is performed by retracting and advancing needle 102 with respect to control portion 104 (e.g., changing the effective length of the needle), rather than by advancing and retracting implant 40. This allows implant 40, once a suitable location has been identified, to be deployed from tool 100 without moving the implant with respect to the surrounding tissue (FIGS. 2G-H).

FIGS. 3A-D show detailed views of tip 120 of needle 102 of tool 100, in accordance with some applications of the invention. Tip 120 has a triple-grind bevel that defines a primary grind 122 (alternatively termed a primary bevel) and two side-grinds 124 (alternatively termed secondary bevels, or lancets). Unlike other triple-grind needles, side-grinds 124 do not extend to meet each other to define a point (i.e., a distal point) at a distal-most part of needle 102 (i.e., at the very tip of the needle). That is, primary grind 122 contributes to the pointedness of the distalmost part 126 of tip 120, but side-grinds 124 do not. Thus, part 126 appears pointed when tip 120 is viewed from the side (e.g., when viewed such that primary grind 122 forms part of the outline of the tip) (e.g., FIG. 3A view D), but appears blunt or rounded when the tip is viewed from above or below (e.g., when viewed such that side-grinds 124 are both visible) (e.g., FIG. 3A views C and F, and FIG. 3B). Therefore, side-grinds 124 converge toward distalmost part 126, but even where they are closest to each other (i.e., at or near to part 126), they are spaced apart by a distance d5.

For some applications, primary grind 122 defines an angle of 15-25 (e.g., 18-22, such as 20) degrees with respect to the lateral wall and/or central longitudinal axis ax1 of needle 102. For some applications, side-grinds 124 converge distally at an angle alpha_1 of 65-85 (e.g., 74-78, such as 76) degrees to each other (see FIG. 3B). For some applications, distance d5 is 0.1-0.4 mm (e.g., 0.16-0.28 mm, such as 0.22 mm).

FIG. 3C shows a transverse cross-section of tip 120 at section III (shown in FIG. 3B), according to some applications of the invention. For such applications, side-grinds 124 face away from primary grind 122. That is, side-grinds 124 are “underneath” the needle, and do not eliminate the sloped surface of primary grind 122. Hence the surface of primary grind 122 is visible in FIG. 3C. In transverse cross-section, the planes of side-grinds 124 are disposed at an angle alpha_2 that is typically 100-150 (e.g., 110-140, e.g., 120-140, such as 130) degrees with respect to each other. For some applications, this is similar to a “back bevel point” needle tip, but without the side-grinds extending to meet each other to define a point at the distal-most part of the needle. Therefore, angle alpha_2 may be described as a back bevel angle.

FIG. 3D shows a transverse cross-section of tip 120, according to some alternative applications of the invention. For such applications, side-grinds 124′ face toward primary grind 122. That is, side-grinds 124′ are on the same side of the needle as primary grind 122, and at the longitudinal portion of the needle at which they are disposed, they eliminate the sloped surface of primary grind 122, leaving a ridge 125. In transverse cross-section, the planes of side-grinds 124′ are disposed at an angle alpha_3 with respect to each other. For some applications, this is similar to a “lancet point” needle tip, but without the side-grinds extending to meet each other to define a point at the distal-most part of the needle. Therefore, angle alpha_3 may be described as a lancet angle.

There is therefore provided, in accordance with some applications of the invention, apparatus for facilitating percutaneous delivery of an implant to a target site of a body of a subject, the apparatus comprising a needle that (1) comprises (a) a distal end; and (b) a proximal end, and (2) defines: (a) a lumen configured to facilitate passage of the implant therethrough, and (b) a triple-grind bevel at the distal end of the needle, the triple-grind bevel defining: (i) a primary grind, and (ii) two side-grinds that do not extend to meet each other to define a point at a distal-most part of the needle.

It is hypothesized by the inventors that tip 120 advantageously has both (i) the tissue-penetrating benefits of existing triple-grind needles, and (ii) a distalmost part that is relatively rounded and less likely to injure a target nerve or an adjacent blood vessel, compared to such existing triple-grind needles.

FIGS. 4A-C show respective views of implant 40. FIG. 4A shows implant 40 in its entirety. As described hereinabove, circuitry 44 and antenna 46 are disposed within implant body 42, and the at least one electrode 48 is disposed on the outside of the implant body. Also as described hereinabove, at least one of electrodes 48 (e.g., distal electrode 48 d) is disposed at distal portion 50 d. Typically, another electrode (e.g., proximal electrode 48 p) is disposed at proximal portion 50 p. Antenna 46 is typically disposed proximally from electrode 48 d (e.g., within proximal portion 50 p).

Implant 40 comprises a cuff 54, which circumscribes a recessed longitudinal portion 56 of implant body 42. FIG. 4B illustrates implant 40 with cuff 54 removed, thereby showing recessed longitudinal portion 56. In the example shown, recessed longitudinal portion 56 is defined by at least part of proximal portion 50 p. However, recessed longitudinal portion 56 may alternatively or additionally be defined by at least part of distal portion 50 d.

Recessed longitudinal portion 56 is radially recessed with respect to at least one other longitudinal portion of the implant body, such that an outer diameter of the recessed longitudinal portion is less than the outer diameter of the other longitudinal portion. In the example shown, the other longitudinal portion may be a longitudinal portion 58 proximal to portion 56 (e.g., another part of proximal portion 50 p), or a longitudinal portion 60 distal to portion 56 (e.g., part of distal portion 50 d). For example, an outer diameter d3 of recessed longitudinal portion 56 is less than an outer diameter d4 of portion 58, and is also less than an outer diameter of portion 60 (which may be the same as diameter d4), and therefore does not include the distal end or the proximal end of the implant.

Cuff 54 is configured to be coupled to implant body 42 by being coupled to (e.g., wrapped around) recessed longitudinal portion 56 such that, when the cuff is coupled to portion 56, an outer diameter d1 of the cuff does not exceed diameter d4. For some applications, cuff 54 extends less than 360 degrees (e.g., 340-355 degrees) around implant body 42. Typically, cuff 54 has a thickness of 100-500 (e.g., 200-250, such as 225) microns.

Cuff 54 defines a plurality of holes 62. Each hole 62 may have a diameter of 200-550 (e.g., 280-340) microns. Cuff 54 typically comprises a resilient material. For some applications, cuff 54 comprises polyether ether ketone, polyethylene terephthalate, fluorinated ethylene propylene, polyimide, acrylic, nylon, polytetrafluoroethylene, or polyetherimide (e.g., Ultem). This material and/or holes 62 increase the resistance of cuff 54, and therefore implant 40, to movement once implanted in tissue (e.g., the cuff grips the tissue). That is, cuff 54 serves as an anchor. Because diameter d1 does not exceed diameter d4, cuff 54 does not grip the inside of needle 102 (i.e., does not increase friction of the implant against the inside of the needle), and thereby does not interfere with movement of implant 40 within the needle during delivery and deployment of the implant. Holes 62 are further configured to facilitate anchoring of implant 40 with respect to the tissue, by facilitating tissue growth into the holes.

FIG. 4C shows implant 40 with electrodes 48 and most of implant body 42 removed, thereby showing antenna 46 and circuitry 44. For some applications, and as shown, antenna 46 is disposed in recessed longitudinal portion 56.

It is to be noted that for some applications tool 100 may be used to deliver implants other than implant 40. For example, tool 100 may be used to deliver a different electrostimulator implant, or an implant that is not an electrostimulator implant. It is to be further noted that, for some applications, needle 102 (e.g., tip 120 thereof) may be used in delivery tools other than tool 100. It is to be further noted that needle 102 may be useful for applications other than percutaneous implantation of an implant.

It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description. 

1.-23. (canceled)
 24. A method for delivering an implant to a target site of a body of a subject, the method comprising: inserting the implant into the subject's tissue; activating the implant to apply a current to the subject's tissue at a first site within the tissue at a first power level; detecting a response of the subject to the application of the current to the first site at the first power level; in response to detecting that the subject responded in a given manner to the application of the current to the first site at the first power level, iteratively applying current to the first site at iteratively lower power levels until detecting that, at a second power level, the subject no longer responds, in the given manner, to the application of current to the first site; and subsequently: moving the implant to one or more further sites within the subject's tissue and applying current to the tissue, at the one or more further sites, at the second power level; detecting a response of the subject to the application of current to the subject's tissue at the one or more further sites; and in response to detecting that the subject responds, in the given manner, to application of the current at the second power level at a given one of the one or more further sites, implanting the implant closer to the given site than to the first site. 25.-36. (canceled)
 37. The method according to claim 24, wherein: the method further comprises, prior to the step of inserting, making an incision in skin of the subject, and the step of inserting comprises inserting the implant into the subject's tissue via the incision.
 38. The method according to claim 24, wherein: detecting the response of the subject to the application of the current to the first site at the first power level comprises measuring a response of the subject to the application of the current to the first site at the first power level, and subsequently detecting the response of the subject to the application of current to the subject's tissue at the one or more further sites comprises subsequently measuring the response of the subject to the application of current to the subject's tissue at the one or more further sites.
 39. The method according to claim 24, wherein: the implant is configured to receive wireless power, and applying the current to the tissue comprises, using the wirelessly received power, applying the current to the tissue.
 40. The method according to claim 39, wherein the step of activating comprises, using the wirelessly received power, activating the implant to apply the current to the subject's tissue at the first site within the tissue at the first power level.
 41. The method according to claim 24, wherein: the implant further includes a cuff, the cuff wrapped around a longitudinal portion of the implant, and the method further comprises, using the cuff, anchoring the implant to the tissue.
 42. The method according to claim 41, wherein the cuff comprises a resilient material.
 43. The method according to claim 41, wherein the cuff comprises an electrically insulating material.
 44. The method according to claim 41, wherein: the longitudinal portion is a recessed longitudinal portion of the implant. 